[1] Natl Res Council CNR, Inst Clin Physiol IFC, I-56124 Pisa, Italy
[2] Univ Padua, Dept Med, I-35128 Padua, Italy
[3] Univ Bologna, S Orsola Hosp, Dept Expt Diagnost & Specialty Med DIMES, Nephrol Dialysis & Renal Transplant Unit, I-40138 Bologna, Italy
[4] Univ Florence, Dept Biomed Expt & Clin Sci Mario Serio, I-50139 Florence, Italy
[5] Fac Med, Dept Med, Serv Bone Dis, CH-1205 Geneva, Switzerland
[6] Geneva Univ Hosp, CH-1205 Geneva, Switzerland
[7] Columbia Univ, Dept Med, Div Nephrol, New York, NY 10032 USA
[8] Osped Riuniti Reggio Calabria, Clin Epidemiol Renal Dis & Hypertens, CNR IFC, I-89124 Reggio Di Calabria, Italy
[9] Univ Padua, Dept Med, Lab Med Unit, I-35128 Padua, Italy
[10] Univ Milan, Dept Biomed & Clin Sci Luigi Sacco, I-20157 Milan, Italy
[11] Univ Padua, Dept Med, Clin Med 1, I-35128 Padua, Italy
[12] Univ Toronto, Univ Hlth Network, Dept Med, 200 Elizabeth St,Eaton North 7-221, Toronto, ON M5G 2C4, Canada